Thread: Magnitude calculation for the M8.1 April 1, 2007 Solomon Islands earthquake

Started: 2007-04-08 15:24:40
Last activity: 2007-04-08 15:24:40
Topics: IRIS EPO
The M8.1 April 1, 2007 Solomon Islands earthquake provides a good
opportunity to calculate the MS magnitude from your AS-1 seismogram. Or,
use the WLIN seismogram (shown in the attachment and available for
download at SpiNet, If your station is
in the western US, an mb magnitude can also be calculated. For central
and eastern US stations, the first arrival is P-diffracted (see map of
theoretical travel times at:
The epicenter to station distance for the WLIN station is 115.29
degrees. The magnitude can be calculated directly in AmaSeis or from
the AS-1 online magnitude calculator
( For the
WLIN seismogram, the MS magnitude is 7.7. The official USGS MS
magnitude is 7.8 calculated by averaging values from 157 stations

-Larry Braile

Lawrence W. Braile, Professor and Department Head
Department of Earth and Atmospheric Sciences
550 Stadium Mall Drive
Purdue University
West Lafayette, IN 47907-2051
(765) 494-5979 (O), (765) 496-1210 (Fax)
E-mail: braile<at> <braile<at>>
Web page:
Departmental web page:
SAGE web page:

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